Well, that stat is for any blunt instrument, not just hammers.
Hammers, clubs, rocks, mugs, chairs, frying pans, bats frozen halibut, sticks, bicycles, pretty much anything that goes "thud" when you hit someone. So, unless hammers account for 70% of all blunt instrument deaths, rifles beats hammers.
I see your point, but you really can't point to any single object in that category like 'hammers,' it is a whole cateory of various objects. But, wandering off topic. Still looking for somepne to explain the connection between hospital infections and guns.